Effects of down collection on incubation temperature, nesting behaviour and hatching success of common eiders (Somateria mollissima) in west Iceland |
| |
Authors: | Thordur ?rn Kristj??nsson J??n Einar J??nsson |
| |
Institution: | (1) Department of Biology, University of Iceland, Askja, Sturlug?tu 7, 107 Reykjav?k, Iceland;(2) University of Iceland, Sn?fellsnes Research Centre, Hafnargata 3, 340 Stykkish?lmur, Iceland |
| |
Abstract: | Incubating common eiders (Somateria mollissima) insulate their nests with down to maintain desirable heat and humidity for their eggs. Eiderdown has been collected by Icelandic
farmers for centuries, and down is replaced by hay during collection. This study determined whether down collecting affected
the female eiders or their hatching success. We compared the following variables between down and hay nests: incubation temperature
in the nest, incubation constancy, recess frequency, recess duration, egg rotation and hatching success of the clutch. Temperature
data loggers recorded nest temperatures from 3 June to 9 July 2006 in nests insulated with down (n = 12) and hay (n = 12). The mean incubation temperatures, 31.5 and 30.7°C, in down and hay nests, or the maximum and minimum temperatures,
did not differ between nest types where hatching succeeded. Cooling rates in down, on average 0.34°C/min and hay nests 0.44°C/min,
were similar during incubation recesses. Females left their nests 0–4 times every 24 h regardless of nest type, for a mean
duration of 45 and 47.5 min in down and hay nests, respectively. The mean frequency of egg rotation, 13.9 and 15.3 times every
24 h, was similar between down and hay nests, respectively. Hatching success adjusted for clutch size was similar, 0.60 and
0.67 in down and hay nests. These findings indicate that nest down is not a critical factor for the incubating eider. Because
of high effect sizes for cooling rate and hatching success, we hesitate to conclude that absolutely no effects exist. However,
we conclude that delaying down collection until just before eggs hatch will minimize any possible effect of down collection
on females. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|